1. Field of the Invention
This invention relates to delay lines and particularly to a recirculating tapped delay line network having a primary electric loop with a selected number of acoustic subloops with the transfer of the signal between the different loops being controlled to provide a maximum number of effective taps with a substantially small amount of signal loss and distortion.
2. Description of the Prior Art
Conventionally, recirculating storage loops utilize coaxial cable or waveguide for the delay element and electrical feedback with gain to maintain recirculation of the signal. Proposed systems include the newer microwave acoustic delay line devices with electrical feedback for providing the recirculation between the input and the output terminals. Thus, existing recirculating tapped delay line loop configurations consists of a tapped delay line either electromagnetic or acoustic with an electrical feedback circuit to coherently recirculate and store desired signals in order to provide a recirculating storage time in the order of one to several milliseconds. To provide a relatively long storage time along with tap spacings of a fraction of microsecond, a large number of acoustic taps and recirculations are required. With conventional electrical recirculation the signal loss and the distortion provided by the transformation between acoustic and electrical signals substantially limits the number of taps that may be utilized. It would be a substantial advantage to the art to have an improved recirculating tapped delay line that provides a large number of effective taps and a large recirculating storage time, all with a minimum of signal distortion and loss